Representatives of more that 50 countries will meet in Vienna shortly to determine the level of international support that Iran receives for its continuing war on drugs.

This comes amid concern about the increasing number of executions for drug-related offences in Iran. Six more people were recently hanged in the city of Kermanshah – executions that a senior figure in the judiciary described as "one of the triumphs of Iran".

As part of the counter-narcotics programme, Iran receives a constant flow of technical support from the UK, the US and other western governments, either directly or through the United Nations Office on Drugs and Crime (UNODC).

Last month, Yury Fedotov, head of the UNODC, said he would "encourage the international community to bolster counter-narcotics" efforts in Iran, Afghanistan and neighbouring countries. However, he made no mention of the consequences of supporting the current Iranian government in this way.

The UNODC started its work in Iran in 1998 – one year after the reformist president Muhammad Khatami came to power on a platform of respect for civil society and the rule of law. It played a crucial role in supporting Iran's health ministry from 2002 to 2005 to implement a "harm reduction" programme to tackle rising rates of drug addiction and HIV.

But progress was reversed when Mahmoud Ahmadinejad became president in 2005. One of his first acts was to appoint a new interior minister: Mostafa Pourmohammadi, an infamous cleric who had ordered and supervised the execution of several thousand political prisoners in 1988.

Ahmadinejad's brother-in-law, Esmail Ahmadi-Moghaddam (the former head of the Basij paramilitary force, and now head of the national police), was put in charge of the technical assistance received by the UNODC. Senior health ministry officials were sacked and many medical professionals, including the world-renowned Alaie brothers, were imprisoned.

Others, like Dr Bijan Nassirimanesh, the founder of the Persepolis NGO clinic, were forced out of Iran. Academics were banned from participating in international conferences and clinics dealing with drug users at a grassroots level have either closed down or had their activities dramatically reduced.

Ahmadinejad also tried to change the nature of Iran's relationship with the UNODC. According to Roberto Arbitrio, a former UNODC field representative in Tehran, Iran made a request in July 2006 to the UNODC for equipment worth $500m, which was "riddled with requests for dual-use items".

It is not clear if Iran received any of these items but a confidential cable released by WikiLeaks appears to show that the head of Iran's drug control department blackmailed the UNODC's representative by suggesting that if the agency did not meet the wishes of Iran, the Islamic republic might "reconsider the scope of its own efforts against the traffickers".

The UNODC and the EU, UK and US seem to have missed the changes Ahmadinejad has made as they have continued to provide invaluable support for its counter-narcotics programme.

Two years into Ahmadinejad's presidency, the UNODC brokered a new deal through the Paris Pact to launch the Triangular Initiative – a programme of support for Iran, Afghanistan and Pakistan in reducing the flow of drugs to the west. As a result, Iran has managed to bypass the sanctions imposed by the UN, the EU and the US to receive body scanners, drug detecting kits, drug catalysts, sniffer dogs, vehicles, night-vision devices and radio communication equipment. It cannot be ruled out that some of this equipment was used by the police to crush the pro-democracy demonstrations in 2009.

In 2010, the British Foreign Office stated in a report that "for … drug-related and political cases, reliable reports continued to emerge of forced confessions, staged trials and a lack of access to independent legal counsel". Despite this, just a few months later, the foreign secretary, William Hague, met Iran's foreign minister and sought "deeper co-operation" between the two countries on counter-narcotics.

This illustrates the systemic contradictions at the heart of the west's approach in dealing with Iran and the wider "global war on drugs". When the head of the UNODC visited Iran in July, he concluded his trip by praising Iran's counter-narcotics strategy as "one of the world's strongest" and called on the international community to assist Iran in its fight. While he was visiting, several more people were executed on drugs charges.

The European parliament has warned against the funding of counter-narcotic programmes that "result in human rights violations, including the application of the death penalty". Given that funding to Iran has increased in recent years, it would seem that in our pursuit to stop the flow of drugs into Europe, these concerns are being overlooked.

If the west is serious about supporting reform in Iran, it must rethink whether it's right for taxpayers to continue funding a programme that leads to the execution of hundreds of people every year.

Human rights campaigners are increasingly worried that funding to combat the narcotics trade is providing indirect assistance to a judicial system that is engaged in what has been described as 'a killing spree of staggering proportions'